BCD Elements

Each BCD element is its own subkey. The name of the subkey is a representation in hexadecimal digits of a DWORD that the BCDEDIT help text refers to as a datatype.

Element Type

The element type is interpreted as bit fields:

Elements whose class is 4 are hidden in the sense that the bcdedit /enum command does not reveal them.

Supported Elements

The following tables list the BCD elements that are yet known in any of several senses. Each is shown first by the numeric constant that represents it in binary code. A second column gives either or both of the symbolic names by which the element seems to be known in source code. The last two columns attend particularly to how the element is worked with through the BCDEDIT tool.

The symbolic name in mixed case and starting with “Bcd” is from the type library in BCDSRV.DLL and is the name to use for programmatic access to the element through the Windows Management Instrumentation (WMI) interface. This symbol is highlighted yellow if it is defined in the type library but is omitted from the BCD Reference in the Windows Vista SDK (dated January 2007).

The symbolic names that are in all capitals and start with “BCDE” are extracted from tables in BCDEDIT.EXE. No use of these names is made by BCDEDIT. Perhaps they were included in BCDEDIT’s tables of elements as an aid during development, such that their persistence in the retail release may be inadvertent (as might happen easily enough if the tables are constructed in the source code by using macros). None of these names are known to be documented.

The friendly name is the one to use with BCDEDIT. It is highlighted yellow if it is not described by any bcdedit /? command. (For completeness, it must be admitted that a few of these are described in BCDEDIT string resources that are not used for help text.)

Library Elements

The following apply to all object types.

The elements 0x11000043, 0x12000044 and 0x16000045 seem not to be documented anywhere. They can be worked with through BCDEDIT only as custom types, e.g., with custom:11000043 where a friendly name might otherwise be used.

Application-Specific Elements

An element whose type has 2 in its most significant 4 bits is interpreted according to its containing object. Note especially that two elements may have the same numerical type but completely different interpretations because they are meant for use with different types of object.

FWBOOTMGR and BOOTMGR Elements

The following elements are known for object types 1XX00001, 1XX00002, 2X200001 and 2X200002. The first two types can be created through BCDEDIT as {fwbootmgr} or {bootmgr}, respectively. For the last two, add the /inherit switch.

OSLOADER Elements

The following elements are known for object types 1XX00003 and 2X200003. The first type can be created through BCDEDIT with the switch /application osloader, the second type either with the /inherit osloader switch or as the built-in {bootloadersettings} object.

The (mis)spelling of BcdOSLoaderInteger_PerformaceDataMemory is Microsoft’s. The BcdOSLoaderInteger_MsiPolicy symbol is documented in the Windows Vista SDK even though the BCDSRV type library does not define it (the documentation and implementation presumably having got out of sync).

The element 0x250000C0 has no friendly name. It can be worked with through BCDEDIT only as a custom type, e.g., with custom:250000C0 where a friendly name might otherwise be used.

RESUME Elements

The following elements are known for object types 1XX00004 and 2X200004. The first type can be created through BCDEDIT with the switch /application resume, the second type either with the /inherit resume switch or as the built-in {resumeloadersettings} object.

Where BCDEDIT lists the pae option among the “entries for the resume loader”, it erroneously describes the option as taking integer values, specifically those of the OSLOADER element to which BCDEDIT gives the same friendly name.

MEMDIAG Elements

The following elements are known for object types 1XX00005 and 2X200005. The first type can be created through BCDEDIT as the built-in {memdiag} object. For the second, use the /inherit memdiag switch.

NTLDR and SETUPLDR Elements

The following elements are known for object types 1XX00006, 1XX00007, 2X200006 and 2X200007. The first type can be created through BCDEDIT as either {legacy} or {ntldr}. The second cannot be created with BCDEDIT. For the last two, use the /inherit ntldr and /inherit setupldr switches, respectively.

STARTUP Elements

The following elements are known for object types 1XX00009 and 2X200009. These types can be created through BCDEDIT with the /application startup and /inherit startup switches, respectively.

Device Elements

The following elements are known for object types 2X3XXXXX and 3XXXXXXX. To create the first type with BCDEDIT, use the /inherit device switch. The second type can be created through BCDEDIT either as the built-in object {ramdiskoptions} or with the /device switch.

Setup Template Elements

The following elements are unknown to BCDEDIT. They have no friendly name and are exempt from enumeration by any bcdedit /enum command.